A rational approach to the treatment of alcohol withdrawal in the ED

Replacing the Clinical Institute Withdrawal Assessment-Alcohol revised with the modified Richmond Agitation and Sedation Scale for alcohol withdrawal to support management of alcohol withdrawal symptoms: potential impact on length of stay and complications

PURPOSE

We evaluated impact on length of stay and possible complications of replacing the Clinical Institute Withdrawal Assessment-Alcohol Revised (CIWA-Ar) scale with a slightly modified Richmond Agitation and Sedation Scale (mRASS-AW) to support managing patients admitted with alcohol withdrawal symptoms in a community hospital. Since mRASS-AW is viewed as easier and quicker to use than CIWA-Ar, provided use of mRASS-AW does not worsen outcomes, it could be a safe alternative in a busy ED environment and offer an opportunity to release nursing time to care.

METHODS

Retrospective time-series analysis of mean quarterly length of stay. All analyses exclusively used our hospital's administrative discharge diagnoses database. During April 1st 2012 to December 14th 2014, the CIWA-Ar was used in the ED and in-patient units to guide benzodiazepine dosing decisions for alcohol withdrawal symptoms. After this point, CIWA-Ar was replaced with mRASS-AW. Data was evaluated until December 31st 2020.

PRIMARY OUTCOME

mean quarterly length of stay.

SECONDARY OUTCOMES

delirium, intensive care unit (ICU) admission, other post-admission complications, mortality.

RESULTS

N = 1073 patients. No association between length of stay and scale switch (slope change 0.3 (95% CI - 0.03 to 0.6), intercept change, 0.06 (- 0.03 to 0.2). CIWA-Ar (n = 317) mean quarterly length of stay, 5.7 days (95% 4.2-7.1), mRASS-AW (n = 756) 5.0 days (95% CI 4.3-5.6). Incidence of delirium, ICU admission or mortality was not different. However, incidence of other post-admission complications was higher with CIWA-Ar (6.6%) than mRASS-AW (3.4%) (p = 0.020).

CONCLUSIONS

This was the first study to compare patient outcomes associated with using mRASS-AW for alcohol withdrawal symptoms outside the ICU. Replacing CIWA-Ar with mRASS-AW did not worsen length of stay or complications. These findings provide some evidence that mRASS-AW could be considered an alternative to CIWA-Ar and potentially may provide an opportunity to release nursing time to care.

A Retrospective Evaluation of Adjunctive Phenobarbital vs. Benzodiazepine Alone for the Treatment of Moderate Alcohol Withdrawal in the Emergency Department

BACKGROUND

Phenobarbital has been used in the emergency department (ED) as both a primary and adjunctive medication for alcohol withdrawal, but previous studies evaluating its impact on patient outcomes are limited by heterogenous symptom severity.

OBJECTIVES

We compared the clinical outcomes of ED patients with moderate alcohol withdrawal who received phenobarbital, with or without benzodiazepines, with patients who received benzodiazepine treatment alone.

METHODS

This is a retrospective cohort study conducted at a single academic medical center utilizing chart review of ED patients with moderate alcohol withdrawal between 2015 and 2020. Patient encounters were classified into two treatment categories based on medication treatment: phenobarbital alone or in combination with benzodiazepines vs. benzodiazepines alone. Chi-square test or Fisher's exact was used to analyze categorical variables and the Student's t-test for continuous data.

RESULTS

Among the 287 encounters that met inclusion criteria, 100 received phenobarbital, compared with 187 that received benzodiazepines alone. Patients who received phenobarbital were provided significantly more lorazepam equivalents. There was a significant difference in the percentage of patient encounters that required admission to the hospital in the phenobarbital cohort compared with the benzodiazepine cohort (75% vs. 43.3%, p < 0.001). However, there was no difference in admission level of care to the floor (51.2% vs. 52.0%), stepdown (33.8% vs. 28%), or intensive care unit (15% vs. 20%), respectively.

CONCLUSIONS

Patients who received phenobarbital for moderate alcohol withdrawal were more likely to be admitted to the hospital, but there was no difference in admission level of care when compared with patients who received benzodiazepines alone. Patients who received phenobarbital were provided greater lorazepam equivalents in the ED.

Prevention of alcohol withdrawal seizure recurrence and treatment of other alcohol withdrawal symptoms in the emergency department: a rapid review

Background

Patients who experience harms from alcohol and other substance use often seek care in the emergency department (ED). ED visits related to alcohol withdrawal have increased across the world during the COVID-19 pandemic. ED clinicians are responsible for risk-stratifying patients under time and resource constraints and must reliably identify those who are safe for outpatient management versus those who require more intensive levels of care. Published guidelines for alcohol withdrawal are largely limited to the primary care and outpatient settings, and do not provide specific guidance for ED use. The purpose of this review was to synthesize published evidence on the treatment of alcohol withdrawal syndrome in the ED.

Methods

We conducted a rapid review by searching MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials (1980 to 2020). We searched for grey literature on Google and hand-searched the conference abstracts of relevant addiction medicine and emergency medicine professional associations (2015 to 2020). We included interventional and observational studies that reported outcomes of clinical interventions aimed at treating alcohol withdrawal syndrome in adults in the ED.

Results

We identified 13 studies that met inclusion criteria for our review (7 randomized controlled trials and 6 observational studies). Most studies were at high/serious risk of bias. We divided studies based on intervention and summarized evidence narratively. Benzodiazepines decrease alcohol withdrawal seizure recurrence and treat other alcohol withdrawal symptoms, but no clear evidence supports the use of one benzodiazepine over another. It is unclear if symptom-triggered benzodiazepine protocols are effective for use in the ED. More evidence is needed to determine if phenobarbital, with or without benzodiazepines, can be used safely and effectively to treat alcohol withdrawal in the ED. Phenytoin does not have evidence of effectiveness at preventing withdrawal seizures in the ED.

Conclusions

Few studies have evaluated the safety and efficacy of pharmacotherapies for alcohol withdrawal specifically in the ED setting. Benzodiazepines are the most evidence-based treatment for alcohol withdrawal in the ED. Pharmacotherapies that have demonstrated benefit for treatment of alcohol withdrawal in other inpatient and outpatient settings should be evaluated in the ED setting before routine use.

Return Encounters in Emergency Department Patients Treated with Phenobarbital Versus Benzodiazepines for Alcohol Withdrawal

INTRODUCTION

Phenobarbital has been successfully used in the emergency department (ED) to manage symptoms of alcohol withdrawal, but few studies have reported outcomes for ED patients who receive phenobarbital and are discharged. We compared return encounter rates in discharged ED patients with alcohol withdrawal who were treated with benzodiazepines and phenobarbital.

METHODS

This is a retrospective cohort study conducted at a single academic medical center utilizing chart review of discharged ED patients with alcohol withdrawal from July 1, 2016, to June 30, 2019. Patients were stratified according to ED management with benzodiazepines, phenobarbital, or a combination of both agents. The primary outcome was return ED encounter within three days of the index ED encounter. Multivariate logistic regression identified significant covariates of an ED return encounter.

RESULTS

Of 470 patients who were discharged with the diagnosis of alcohol withdrawal, 235 were treated with benzodiazepines, 133 with phenobarbital, and 102 with a combination of both. Baseline characteristics were similar among the groups. However, patients who received phenobarbital were provided significantly more lorazepam equivalents compared to patients who received benzodiazepines alone. Treatment with phenobarbital, alone or in combination with benzodiazepines, was associated with significantly lower odds of a return ED visit within three days compared with benzodiazepines alone [AOR 0.45 (95% CI 0.23, 0.88) p = 0.02 and AOR 0.33 (95% CI 0.15, 0.74) p = 0.007].

CONCLUSIONS

Patients who received phenobarbital for alcohol withdrawal were less likely to return to the ED within three days of the index encounter. Despite similar baseline characteristics, patients who received phenobarbital, with or without benzodiazepines, were provided greater lorazepam equivalents the ED.

Substances of abuse and the blood brain barrier: Interactions with physical exercise

Substance use disorders pose a common medical, social and financial problem. Among the pathomechanisms of substance use disorders, the disruption and increased permeability of the blood-brain barrier has been recently revealed. Physical exercise appears to be a relatively inexpensive and feasible way to implement behavioral therapy counteracting the blood-brain barrier impairment. Concomitantly, there are also studies supporting a potential protective role of selected substances of abuse in maintaining the blood-brain barrier integrity. In this review, we aim to provide a summary on the modulatory influence of physical exercise, a non-pharmacological intervention, on the blood-brain barrier alterations caused by substances of abuse. Further studies are needed to understand the precise mechanisms that underlie various effects of physical exercise in substance use disorders.

Management of Alcohol Withdrawal in the Emergency Department: Current Perspectives

Alcohol withdrawal syndrome (AWS) is a common, heterogenous, and life-threatening complication of alcohol use disorder (AUD). AUD is a leading cause of worldwide mortality, and many patients with AUD will develop AWS during their ED course. This review summarizes the epidemiology, pathology, and management of AWS and AUD in the emergency setting. The time course of AWS and its impact on ED treatment is emphasized. Once AWS is diagnosed, symptom-triggered benzodiazepine administration remains the most commonly provided treatment but may not be appropriate for patients with significant medical or psychiatric comorbidity or pending discharge. In these cases, ED clinicians may consider short courses of barbiturates or alternative regimens based on novel anticonvulsants. Specific treatment protocols are enumerated for clinical practice. Finally, emergency providers must not only manage acute patients' AWS but also lay the foundation for successful treatment of AUD. An approach to the disposition of the patient with AUD is presented. The authors examine shortcomings in the extant literature and suggest opportunities for further study.

Risk Factors for Severe Alcohol Withdrawal Syndrome in an Acute Hospital Population

BACKGROUND

The literature lacks consensus to the factors that increase the risk of a patient developing severe alcohol withdrawal syndrome (SAWS).

AIM

The study set out to identify the variables that increase the risk of SAWS in patients who have alcohol dependence syndrome.

METHODS

A case-control study was designed to investigate the variables associated with SAWS in an acute hospital setting. Three hundred eighty-two case and 382 control patients were randomly selected retrospectively from referrals to the acute addiction liaison nursing service during a 12-month period (January 1, 2015, to December 31, 2015). Statistical significance (p < .05) and association with SAWS were calculated using chi-square, Cramer's V test, odds ratio, and Levene's test.

RESULTS

Twenty-four variables have been identified as associated with SAWS development. Five of the 24 variables had a moderate-to-strong association with SAWS risk: Fast Alcohol Screening Test, Glasgow Modified Alcohol Withdrawal Scale score, AWS admission, hours since the last drink, and systolic blood pressure. The study also identified that comorbidity was associated with not developing SAWS.

CONCLUSION/RECOMMENDATIONS

These findings confirm that noninvasive variables collected in the emergency department are useful in identifying a person's risk of developing SAWS. The results of this study are a useful starting point in the exploration of SAWS and the development of a tool for use in the emergency department that can stratify risk into high and low and is the next stage of this program of work.

Development of an alcohol withdrawal risk stratification tool based on patients referred to an addiction liaison nursing service in Glasgow

Purpose

The purpose of this paper is to develop an alcohol withdrawal syndrome risk stratification tool that could support the safe discharge of low risk patients from the emergency department.

Design/methodology/approach

A retrospective cohort study that included all patients referred to the acute addiction liaison nursing service over one calendar month (n=400, 1–30 April 2016) was undertaken. Bivariate and multivariate modelling identified the significant variables that supported the prediction of severe alcohol withdrawal syndrome (SAWS) in the cohort population.

Findings

The Glasgow Modified Alcohol Withdrawal Scale (GMAWS), hours since last drink, fast alcohol screening test (FAST) and systolic blood pressure correctly identified 89 per cent of patients who developed SAWS and 84 per cent of patients that did not. Increasing each component by a score of one is associated with an increase in the odds of SAWS by a factor of 2.76 (95% CI 2.21, 3.45), 1.31 (95% CI 1.24, 1.37), 1.30 (95% CI 1.08, 1.57) and 1.22 (95% CI 1.10, 1.34), respectively.

Research limitations/implications

The research was conducted in a single healthcare system that had a high prevalence of alcohol dependence syndrome (ADS). Second, the developed risk stratification tool was unable to guarantee no risk and lastly, the FAST score previously aligned to severe ADS may have influenced the patients highest GMAWS score.

Practical implications

The tool could help redesign the care pathway for patients who attend the emergency department at risk of SAWS and link low risk patients with community alcohol services better equipped to deal with their physical and psychological needs short and long term supporting engagement, abstinence and prolongation of life.

Originality/value

The tool could help redesign the care pathway for emergency department patients at low risk of SAWS and link them with community alcohol services better equipped to deal with their physical and psychological needs, short and long term, supporting engagement, abstinence and prolongation of life.

Correlation between the epigenetic modification of histone H3K9 acetylation of NR2B gene promoter in rat hippocampus and ethanol withdrawal syndrome

Patients with alcohol use disorder may develop acute ethanol withdrawal syndrome (EWS). Previous studies showed that an epigenetic modification of the N-methyl-D-aspartate (NMDA) receptor, especially NMDA receptor 2B subunit (NR2B), was involved in the pathological process of EWS. However, the relationship between the epigenetic regulation of the NR2B gene in the rat hippocampus region and EWS were inconsistent. The purpose of this study was to explore the role of the histone H3K9 acetylation of the NR2B gene in the rat hippocampus region in EWS. A rat model of chronic ethanol exposure was established. EWS score and the behavioral changes were recorded at different time points. The NR2B expression levels and the histone H3K9 acetylation level in the NR2B gene promoter region were measured using qRT-PCR, Western blot, immunofluorescence, and chromatin immunoprecipitation, respectively. Finally, the relationship between the epigenetic modification of histone H3K9 acetylation of NR2B gene promoter and EWS were examined. Our ultimate results showed that the EWS score was increased at 2 h, peaked at 6 h after withdrawal of ethanol, and reduced to the level parallel to the normal control group at day 3 after ethanol withdrawal. The NR2B mRNA expression and protein levels showed similar patterns. Further correlation analyses indicted that both histone H3K9 acetylation in NR2B gene promoter and the expression levels of NR2B were positively associated with EWS. Our results suggest that chronic ethanol exposure may result in epigenetic modification of histone H3K9 acetylation in NR2B gene promoter in rat hippocampus, and the expression levels of NR2B were found to be positively correlated with ethanol withdrawal syndrome.

Evaluation of a Web-based Educational Program to Teach the Identification and Management of Alcohol Withdrawal in the Emergency Department

BACKGROUND

Ideal management of alcohol withdrawal syndrome (AWS) incorporates a symptom-driven approach, where patients are regularly assessed using a standardized scoring system (Clinical Institute Withdrawal Assessment for Alcohol-Revised [CIWA-Ar]) and treated according to severity. Accurate administration of the CIWA-Ar requires experience, yet there is no training program to teach this competency. The objective of this study was to develop and evaluate a curriculum to teach clinicians how to accurately assess and treat AWS.

METHODS

This was a three-phase education program consisting of a series of e-learning modules containing core competency material, an in-person seminar to orient learners to high-fidelity simulation, and a summative evaluation in an objective structured clinical examination setting using a standardized patient. To determine the impact of the AWS curriculum, we recorded how often the CIWA-Ar was appropriately applied in the emergency department (ED) before and after training. A CIWA-Ar protocol breach was defined as inappropriate administration of benzodiazepines (CIWA-Ar < 10) and failure to administer benzodiazepines when required (CIWA-Ar ≥ 10). ED length of stay, amount of benzodiazepines administered in the ED, discharge prescriptions, and unit doses (take-away bottle of four tablets) of benzodiazepine given were recorded.

RESULTS

Seventy-four ED nurses completed the curriculum over an 8-week period. In the 5 months prior to the educational program delivery, we identified 144 of 565 (25.5%) CIWA-Ar protocol breaches, compared to 64 of 547 (11.7%) in the 5 months after training (∆13.8%, 95% confidence interval [CI] = 9.3%-18.3%). Program completion resulted in a reduction in the median total dose of diazepam administered in the ED (40 mg vs. 30 mg, ∆10 mg, 95% CI = 0-20 mg) and no change was detected in ED length of stay and benzodiazepines prescribed.

CONCLUSIONS

Completion of this curriculum resulted in better compliance with the CIWA-Ar protocol by those who administer the CIWA-Ar; however, changes in inappropriate benzodiazepine prescribing practice will require future interdisciplinary initiatives.

Impact of an Alcohol Withdrawal Treatment Pathway on Hospital Length of Stay: A Retrospective Observational Study Comparing Pre and Post Pathway Implementation

OBJECTIVE

To determine if the implementation of a hospital-specific alcohol withdrawal treatment pathway used in a medical-surgical patient population decreased hospital length of stay (LOS) compared with the standard of care.

METHODS

This retrospective observational study, conducted in a large academic tertiary care hospital, involved 582 subjects who met criteria for study inclusion, with 275 subjects in the 2010 cohort and 307 in the 2012 cohort. The Alcohol Withdrawal Project Team was formed with the goal of creating a standardized approach to the recognition and treatment of alcohol withdrawal at Duke University Hospital. The group created a computerized physician order entry alcohol withdrawal treatment pathway with 4 possible treatment paths chosen on the basis of current withdrawal symptoms, vital signs, and alcohol withdrawal history. The 4 treatment paths are 1 prophylaxis; 2 mild-to-moderate withdrawal; 3 moderate-to-severe withdrawal, and 4 severe withdrawal/alcohol withdrawal delirium. Each treatment path corresponds to a different lorazepam dose and dose schedule and symptom assessment. This pathway was implemented in the hospital at the end of 2011.

RESULTS

Using a Cox proportional hazards model and adjusting for covariates, there was a 1 day [95% confidence interval (CI), 1-2 d] reduction in median hospital LOS between the 2010 and 2012 cohorts, 5 versus 4 days, respectively. The average ratio in hospital LOS between the 2 cohorts was 1.25 (95% CI, 1.25-1.67). The CI was estimated by bootstrapping and indicated a significantly longer LOS in the 2010 cohort compared with the 2012 cohort. Nonsignificant changes were found in the proportion of subjects admitted to the intensive care unit (24% in 2010 vs. 29.3% in 2012), LOS in the intensive care unit (7.1±8 d in 2010 vs. 5.6±6.9 d in 2012), and proportion of patients discharged with a diagnosis of delirium tremens (17.8% in 2010 vs. 15.3% in 2012).

CONCLUSIONS

This study demonstrates the successful implementation of an alcohol withdrawal treatment pathway in a medical-surgical population hospitalized in a large tertiary care facility with significant impact on hospital LOS.

The emergency medicine management of severe alcohol withdrawal

INTRODUCTION

Alcohol use is widespread, and withdrawal symptoms are common after decreased alcohol intake. Severe alcohol withdrawal may manifest with delirium tremens, and new therapies may assist in management of this life-threatening condition.

OBJECTIVE

To provide an evidence-based review of the emergency medicine management of alcohol withdrawal and delirium tremens.

DISCUSSION

The underlying pathophysiology of alcohol withdrawal syndrome (AWS) is central nervous system hyperexcitation. Stages of withdrawal include initial withdrawal symptoms, hallucinations, seizures, and delirium tremens. Management focuses on early diagnosis, resuscitation, and providing medications with gamma-aminobutyric acid (GABA) receptor activity. Benzodiazepines with symptom-triggered therapy have been the predominant medication class utilized and should remain the first treatment option with rapid escalation of dosing. Treatment resistant withdrawal warrants the use of phenobarbital or propofol, both demonstrating efficacy in management. Propofol can be used as an induction agent to decrease the effects of withdrawal. Dexmedetomidine does not address the underlying pathophysiology but may reduce the need for intubation. Ketamine requires further study. Overall, benzodiazepines remain the cornerstone of treatment. Outpatient management of patients with minimal symptoms is possible.

CONCLUSIONS

Alcohol withdrawal syndrome can result in significant morbidity and mortality. Physicians must rapidly diagnose these conditions while evaluating for other diseases. Benzodiazepines are the predominant medication class utilized, with adjunctive treatments including propofol or phenobarbital in patients with withdrawal resistant to benzodiazepines. Dexmedetomidine and ketamine require further study.

Diazepam in the Treatment of Moderate to Severe Alcohol Withdrawal

Benzodiazepines ameliorate or prevent the symptoms and complications of moderate to severe alcohol withdrawal, which can include autonomic hyperactivity, agitation, combativeness, hallucinations, seizures, delirium, and death. The benzodiazepines most commonly used for this purpose are lorazepam, chlordiazepoxide, oxazepam, and diazepam. It is widely asserted that no member of this group is superior to the others for treatment of alcohol withdrawal. However, of these, diazepam has the shortest time to peak effect, which facilitates both rapid control of symptoms and accurate titration to avoid over-sedation. Furthermore, diazepam and its active metabolite, desmethyldiazepam, have the longest elimination half-lives, so their levels decrease in a gradual, self-tapering manner, resulting in a smoother withdrawal, i.e., a lower incidence and severity of both breakthrough symptoms and rebound phenomena, including a possibly decreased seizure risk. Importantly, the fear of increased risk of over-sedation with diazepam compared with other benzodiazepines is based on a misunderstanding of its pharmacokinetics and is unfounded. Similarly, the notion that diazepam should be avoided in patients with liver disease and elderly patients to avoid prolonged over-sedation is based on no more than conjecture. In fact, there is clinical evidence that diazepam is safe for the treatment of alcohol withdrawal in these patients when administered using a simple symptom-based approach. There is one instance in which diazepam should not be used: when intramuscular administration is the only option, the lipophilicity of diazepam can result in slow absorption-either lorazepam or, when rapid control of symptoms is required, midazolam should be used. The comparative pharmacokinetics of the benzodiazepines used in the treatment of alcohol withdrawal together with a comprehensive review of the literature on their use strongly suggest that diazepam should be the preferred benzodiazepine for the treatment of patients experiencing moderate to severe alcohol withdrawal under most circumstances.

Comparison of enteral ethanol and benzodiazepines for alcohol withdrawal in neurocritical care patients

We designed a study to evaluate the use of benzodiazepines and ethanol in patients being assessed for alcohol withdrawal and compare outcomes between the two agents. This is a retrospective chart review of patients admitted to neurocritical care or neurosurgical services who were at risk for ethanol withdrawal between June 2011 and September 2015. Patients were divided into two groups based on the first medication administered for alcohol withdrawal management, either benzodiazepine (n=50) or enteral ethanol (n=50). The primary endpoint was the maximum change in Clinical Institute Withdrawal Assessment of Alcohol scale (CIWA) score within the first 24hours. Secondary endpoints included maximum and minimum CIWA score in 5days, length of stay, and change in Glasgow Coma Scale. Study groups differed by mortality risk, level of coma at admission, and other clinical characteristics, with the ethanol group appearing less severely ill. There was no significant difference between the two groups in the maximum change in CIWA score at 24hours (-0.97, 95%CI: -3.21 to 1.27, p=0.39). Hospital and intensive care unit length of stay was 6.5 days and 1 day shorter for the ethanol group (p=0.03 and p=0.02, respectively). In summary, enteral ethanol was preferentially used in patients who are more likely to be capable of tolerating oral intake. We found that the change from baseline in CIWA score or other physiologic variables was not substantially different between the two agents. The overall utility of benzodiazepines and enteral ethanol remains unclear for this population and further study is needed to determine superiority.

Alcohol and Heart Disease in the Forensic Setting

The impacts of chronic high levels of ethanol consumption on cardiovascular structure and function are reviewed as they pertain to forensic pathology practice. Both hypertrophy and remodeling of the myocardium as well as physiological revision of electrical conduction through the heart can occur in a progressive fashion. A discussion about the likely underappreciated spectrum of structural heart disease that may be seen in individuals with chronic alcohol dependence is presented. Finally, brief reference to the collision between alcohol, cardiovascular disease, and forensically relevant scenarios is provided.

Operant alcohol self-administration in dependent rats: focus on the vapor model

Alcoholism (alcohol dependence) is characterized by a compulsion to seek and ingest alcohol (ethanol), loss of control over intake, and the emergence of a negative emotional state during withdrawal. Animal models are critical in promoting our knowledge of the neurobiological mechanisms underlying alcohol dependence. Here, we review the studies involving operant alcohol self-administration in rat models of alcohol dependence and withdrawal with the focus on the alcohol vapor model. In 1996, the first articles were published reporting that rats made dependent on alcohol by exposure to alcohol vapors displayed increased operant alcohol self-administration during acute withdrawal compared with nondependent rats (i.e., not exposed to alcohol vapors). Since then, it has been repeatedly demonstrated that this model reliably produces physical and motivational symptoms of alcohol dependence. The functional roles of various systems implicated in stress and reward, including opioids, dopamine, corticotropin-releasing factor (CRF), glucocorticoids, neuropeptide Y (NPY), γ-aminobutyric acid (GABA), norepinephrine, and cannabinoids, have been investigated in the context of alcohol dependence. The combination of models of alcohol withdrawal and dependence with operant self-administration constitutes an excellent tool to investigate the neurobiology of alcoholism. In fact, this work has helped lay the groundwork for several ongoing clinical trials for alcohol dependence. Advantages and limitations of this model are discussed, with an emphasis on what future directions of great importance could be.

A neurologist's approach to delirium: diagnosis and management of toxic metabolic encephalopathies

Toxic metabolic encephalopathies (TMEs) present as an acute derangement in consciousness, cognition and behavior, and can be brought about by various triggers, including endocrine and metabolic disturbances, exogenous toxins, pain and infection. Also referred to as "delirium" or "acute confusional states," TMEs are characterized by (1) an altered level of consciousness and activity, (2) global changes in cognition with inattention, (3) a fluctuating course with disturbances in the sleep-wake cycle, and (4) asterixis and myoclonus. The pathophysiology of this syndrome is poorly understood. Imbalanced neurotransmitter signaling and pathologically heightened brain inflammatory cytokine signaling have been proposed as candidate mechanisms. Focal brain lesions can also occasionally mimic TMEs. A neurological examination is required to identify the presence of focal findings, which when present, identify a new focal lesion or the recrudescence of prior ischemic, inflammatory or neoplastic insults. Diagnostic testing must include a search for metabolic and infectious derangements. Offending medications should be withdrawn. Magnetic resonance imaging, cerebrospinal fluid analysis and electroencephalography should be considered in select clinical situations. In addition to being an unpleasant experience for the patient and family, this condition is associated with extended hospital stays, increased mortality and high costs. In individuals with diminished cognitive reserve, episodes of TME lead to an accelerated decline in cognitive functioning. Starting with an illustrative case, this paper provides a neurologist's approach to the diagnosis, differential diagnosis and management of toxic metabolic encephalopathies.